Die casting machines



July 17, 1956 5. SMITH 2,754,557

. DIE CASTING MACHINES Filed Feb. 21, 1955 United States Patent 2,754,557 DIE CASTING MACHINES Stanley Smith, Sutton Coldfield, England, assignor to E. M. B. Company Limited, West Bromwich, England Application February 21,1955, Serial No. 489,673

Claims priority, application Great Britain March 19, 1954 2 Claims. (CI. 22-68) This invention relates to die casting machines of the kind adapted to deal with aluminum, brass or other metals having melting points substantially higher than those of the low-melting point metals such as zinc-base alloys. A typical machine comprises a fixed platen on which is secured a part of the mould into which the metal is to be injected, a slidable platen carrying the other part of the mould, fluid operable means for actuating the second platen, a feed cylinder secured horizontally to the said fixed platen and adapted to receive a quantity of metal appropriate to the casting to be produced, and a fluid-operable plunger for ejecting the metal from this cylinder to the mould.

In such a machine when dealing with aluminum or brass or other metal having a comparable melting point, it is necessary to effect the transference of the metal torthe mould in the shortest practicable time interval, and adequate power must be provided not only for moving the plunger rapidly but also with sufficient force to overcome the resistance encountered in the transition of the metal from the cylinder to the mould. The power required is usually large, and always at least slightly in excess of the duty to be performed, in order to deal with any normal irregularity in the resistance to be overcome by the plunger.

It not infrequently happens that, due to for example excessively rapid chilling of the metal in some part of the mould, an abnormal obstruction to flow is encountered, with the result that a large part of the power available is absorbed in shock, with consequent risk of injury to the machine. To elucidate this point, an analogy may be mentioned. When a drop hammer is used for forging a hot mass of metal, the greater part of the energy of the falling hammer head is utilised in shaping the metal. But if the metal happens to be insufliciently soft, the energy would be mainly or wholly absorbed in the anvil supporting the metal, and the resulting shock might in an extreme case be sutlicient to break the anvil. A similar condition can occur in a die casting machine when a large amount of power is required for transferring the metal to the mould in a short time interval.

The object of the present invention is to enable the machine to be protected against the injurious effects of excessive shocks.

The invention comprises the combination of a horizontal bed, a platen adapted to carry one of the mould parts, a relatively slidable platen adapted to carry the other mould part, fluid-operable means for injecting the metal into the mould, and fluid operable means for moving the second platen, both of the said fluid operable means being ice anchored to the first platen and being slidably mounted on the bed, and the first platen being anchored to the bed by resilient means.

In the accompanying drawing is shown in part-sectional side elevation a die casting machine incorporating the present invention.

In the illustrated example there is provided a horizontal bed 1, and to the bed is secured by resilient means a platen 2 adapted to carry one of the mould parts (not shown). The resilient means in one convenient form consists of a flexible steel plate 3 mounted in a vertical plane and secured at its upper and lower edges to angle pieces 4 and 5 which are respectively secured to the lower edge of the platen 2 and the bed 1.

At one side of the platen 2 there are slidably supported on the bed 1 the means 6 for injecting the molten metal into the mould, these means being anchored to the platen 2 by horizontal tie rods 7, one only of which is seen in the drawing.

At the opposite side of the platen 2 is arranged the relatively slidable platen 8 for carrying the other part of the mould. This platen 8 is movable by other fluid operable means 9 freely s'lidable on the bed 1, these means 9 being also anchored to the platen 2 by horizontal tie rods 10 on which the platen 8 can slide. The platen 8 is mov able towards and away from the first platen by toggles 9a forming part of the fluid operable means 9.

The arrangement is such that during normal working conditions the blow exerted on the machine by the feed plunger associated with the means 6 at the end of each injection operation is inadequate to etfect more than a small flexure of the steel plate 3. But an abnormally heavy blow results in a relatively large flexure of the plate 3 with a corresponding movement of the parts of the machine freely supported on the bed 1, the shock being then absorbed by the friction between the said parts and the bed. Subsequent to this movement the parts are restored to their normal position by the resilient return of the plate 3 to its normal condition.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A die casting machine comprising the combination of a horizontal bed, a platen adapted to carry one of the mould parts, a relatively slidable platen adapted to carry the other mould part, fluid-operable means for injecting the metal into the mould, and fluid operable means for moving the second platen, both of the said fluid operable means being anchored to the first platen and being slidably mounted on the bed, and the first platen being anchored to the bed by resilient means.

2. A die casting machine as claimed in claim 1, in which the resilient means is a vertically arranged flexible steel plate the upper edge of which is secured to the first platen, Whilst the lower edge is secured to the bed.

References Cited in the file of this patent UNITED STATES PATENTS 1,219,357 Stewart Mar. 13, 1917 1,627,784 Korsmo May 10, 1927 1,954,775 During et al Apr. 10, 1934 2,220,776 Smith Nov. 5, 1940 2,233,354 Thilenius Feb. 25, 1941 2,334,372 Abbott et a1. Nov. 16, 1943 

